Had this problem for a while and finally just have to break down and ask for help. I try no to start threads unless I absolutly have to.

My charging system has been kinda out of whack for sometime now. When I bought the blazer the old factory alt was going so I replaced it with a 140 amp Powemaster alt from Advance. Well my lights would dim because of my stereo and all and I figured it was just because of the extra load of the amp. But after a while I picked up a small voltmeter that plugged into the cigg lighter just to keep an eye on my drops.

Well I noticed that one day just sitting at idle in the drive thru of a resturant, my voltage was about 12.8-13 volts. Just idling waiting, no lights, stereo volume on maybe 5 just barly hear it, no AC/heat. I turn my headlights on and the volts drop .2-.5 volts. Dips up and down with the blinkers. At start up I get about 14-14.2 volts, and while driving it varies between 13.4-13.6 on average. And that's without headlight, stereo, or anything, just plain driving. The battery shows about 11.8 when the engine is off.

What might be causeing this? I recently pulled the 140amp alt and replaced it with a 250 amp built AD244 alternator, still have the same problems. Big 3 wiring done in 1/0 gauge wire. All connections look good. I'm starting to run out of ideas. Besides just pulling my dash out and checking factory wiring to see if something is broke/loose/someone tampered with it before I got it. Anyone else experinced such a problem? I know 13.6 volts at idle with no extra loads on the system aint right. I'm gonna run new 1/0 wire for the amplifier and clean up some of the wiring under the hood and see if that helps. Any ideas would be greatly appriciated.

I'm gonna pick up a multimeter hopefully tomarrow and tinker with it after work, and really dedicate some time to it this weekend.

Normally stays around here when driving.



Saw this sitting at idle for about 8-10 minutes. No loads, just engine running.

And I won't even get into the drops when the stereo is turned up...

 

Seems about normal for me. My 90 is and has been the same ay forever

 

I have the same thing even tho mine is an 03. Never really payed too much attention to it but its concerning me now. It used to run at 14.5-15 ALL the time but now i never see it past or even ON the 14 volt line.

I know you just replaced the ALT so thats leading me to thing its my battery. I didn't have a cap for a few months and pounded my system, then got a cap and pounded it harder, then read the "story" about caps on here and took it out and it seemed to have stated after I took my cap out.

ANY help would be appreciated...For both of us!

 

I have a few things I'm gonna do this weekend. I'm gonna check ALL my grounds. Battery to frame and engine block to frame, amp ground, chassis to frame straps, (might add one or two more of them). Plus I'm gonna eliminate all the wiring I can. All the factory wires that the big 3 replaces are coming out. The 6 gauge my dad added into the factory power cable for the alt, all that. Clean all the grounds that I find and spray over them with undercoating.

Also picked up a automotive multimeter from Harbor Freight and am gonna test some voltage levels in diffrent areas to see if I can find a short anywhere. I'll let you know if anything helps. Mines never been at 14.5 like most people. I'm tired of my lights blowing from them surging with the stereo and mo volts dropping to like 11.8-12 if I have the ac on at idle! lol